The present invention relates generally to injection molding apparatus and, more particularly, to apparatus for producing liquid storage containers. More specifically, the invention is directed to a manufacturing system wherein thermoplastic material is injection molded together with a base material to produce a container having integrally formed top and bottom closure members, with the bottom closure member being attached in a manner enabling bottom filling of the container and subsequent sealing thereof by completing attachment of the bottom closure member.
Numerous types of liquid containers are known which may be used, for example, for storing milk, juices or other types of soft drinks. The packages for such liquids are preferably block-shaped non-returnable members formed of a cardboard material coated with polyethylene on the inner side thereof.
In forming such packages or containers, blanks for the containers are, as a rule, produced in one piece and they are folded into the finished container shape with one or more connecting seams being required. Where a polyethylene coating is used, the seams may be heat sealed together.
Two important characteristics of liquid packaging, particularly packaging of the non-returnable type, are the seal tightness of the container and its ability to be easily opened for dispensing the liquid contained therein. The present invention is directed to an arrangement which is particularly effective in producing a liquid packaging member having these characteristics incorporated therein. The invention overcomes several disadvantages of prior art packaging arrangements particularly with regard to the effectiveness of the ability of the container to store the liquid and the ease with which liquid dispensing may be effected. For example, in a milk container previously known, a seam is formed at the top of the container and the seam is arranged to provide an opening by means of a perforation located at one end of the container in the vicinity of a narrow edge thereof. Before such a container is opened, the corners provided with the perforation lines must be displaced upwardly as the uppermost fold edge is torn open. Then, each cardboard strip must be torn off along the perforation line and the seal strip also is torn off without being opened. This type of a container provides significant difficulty in tearing open its closure. However, this disadvantage is tolerated since it is necessary to provide an absolutely liquid-tight package which is also fairly economical to produce. Accordingly, it will be appreciated that the solution afforded by this type of packaging is not completely satisfactory.
There are other types of non-returnable packaging containers of the prior art which require a tool, such as a knife, a scissors or the like, for opening of the container. Such packaging is not considered satisfactory because the opening requires such a tool which the consumer may not always have readily available.
Based upon the above-mentioned disadvantages, a liquid packaging member formed of cardboard or similar material and a process for forming such a container have been developed wherein there is utilized a pouring spout for opening the container and dispensing the liquid therefrom. In various known types of pouring spouts, the edges thereof have been sealed closed so that during storage of the liquid an effective seal is assured. When the container is to be used, the seam closing the spout may be torn open in an advantageous manner which requires considerably less effort than is needed with packaging members previously mentioned. Furthermore, by providing a special shape for the pouring spout, it is possible to provide an arrangement which makes it easier to direct the liquid being poured from the container.
Known types of packaging members may be further simplified to save costs in a number of various ways.
Accordingly, it is a primary object of the present invention to provide a simplified packaging arrangement for liquids without sacrificing the seal tightness of the container or its ease of opening for the practical and effective dispensing of the liquid contained therein. Additionally, the invention is intended to simplify the process for producing packaging members of the type discussed herein and to reduce the cost of the machinery required in the production operation. Furthermore, it is possible to utilize less expensive materials in a more effective manner.